Cooked roach solves fossil chemical problem suggests an article in news@nature, 26 July 2006. A team led by organic chemist Neal Gupta of the University of Bristol have solved a chemical puzzle on the difference between living and fossil arthropod exoskeletons. Living arthropods, a large group of invertebrates, such as insects, crabs and millipedes, have exoskeletons made of fibres similar to cellulose embedded in a matrix protein, with a waxy layer on the surface. The exoskeletons of fossilised arthropods are mainly made up of long chain carbon compounds called aliphatic molecules that are similar to molecules found in fossil fuels. To see if the aliphatic molecules could be derived from chitin by fossilisation processes Gupta's team took exoskeletons from cockroaches, scorpions and shrimps and baked them at 350 degrees Celsius and 700 atmospheres pressure for one day. The researchers claim this treatment "mimics the way fossils form over millions of years, compressed into a single day by upping the temperature." The roast "fossils" did contain aliphatic molecules similar to those of more conventionally formed fossils. The researchers concluded that aliphatic molecules were derived from the waxy layer and possibly from the internal tissues of the animals. The team hope their technique will help to understand how fossil fuels form.

Editorial Comment: This experiment reminds us that it doesn't take time to make fossils - it takes the right physical and chemical processes. The 700 atmospheres pressure is quite a realistic model for many deeply buried fossil fuels. As such, this experiment adds to the evidence that fossils and fossil fuels were actually formed by rapid deep burial in a brief time span, not slowly and gradually over millions of years. The very weight of the sediments becoming one source of the heat to cook them. This editor’s research on the rapid formation of fossil fuels has shown that the similar chemical changes to those that occurred in this experiment can be produced equally rapidly, but at lower temperatures, if the organic matter is baked with clays which seem to act as a catalyst. (Ref. time, chemistry, hydrocarbons)